Ground -surface adaption device for attachments on harvesting machines

ABSTRACT

The invention relates to a device for adapting attachments on harvesting machines to the ground surface, in particular for combine harvesters and forage harvesters. The aim of the invention is to produce a rapid adaptation to the ground surface, even at high speeds, that is extremely accurate and also cost-effective. To achieve this, a feed device ( 1 ), whose height can be adjusted by a hydraulic cylinder ( 5 ). has a shaft ( 7 ) which is aligned transversally to the direction of travel, the attachment ( 15 ) being mounted so that it can be rotated through a defined pivoting angle ( 9 ) about said shaft. The pivoting angle ( 9 ) can be modified by means of a hydraulic working cylinder ( 10 ) which connects the feed device ( 1 ) and the attachment ( 15 ), whereby the pivoting angle ( 9 ) is continuously monitored by a sensor ( 11 ). An additional sensor ( 18 ) continually measures the distance ( 17 ) of the attachment ( 15 ) to the ground surface. Both sensors ( 11; 18 ) are connected to the hydraulic systems of the hydraulic cylinder ( 5 ) and the hydraulic working cylinder ( 10 ) via a controller ( 40 ).

[0001] The invention concerns a device for ground copying for front attachments to harvesting machines, especially for self-propelled combine harvesters and forage choppers, in accordance with the features in the generic terms of claim 1.

[0002] Such devices for ground copying serve to adjust the front attachments to the unevenness of the ground, so that the crop can be harvested without loss even under these conditions. For this it is adequately known to fix the attachments to the harvesting machine so that they can swivel, so that on the one hand the so-called longitudinal movement of copying can be executed along the axis transverse to the direction of travel of the machine and on the other hand transverse copying can be effected along an axis pointing in the direction of travel. The cases for the application of such devices for ground copying extend to cutting and mowing machines of all types of construction and to gathering devices on the most varied types of harvesting machines. Therefore they have become so important, as all these attachments must have an appropriately wide working width because of the very high productive capacity of the present-day harvesting machines. In the state of the art a multitude of variant embodiments for this have already become known, which can be divided into two large categories.

[0003] The first category is described in EP 0 331 893B1, in which the attachment is fixed on the front side of the harvesting machine so that it can tilt for the purpose of copying longitudinally and transversely. Two hydraulic cylinders arranged at a distance from each other and symmetrically about the central longitudinal axis of the harvesting machine support the attachment from below with a force such that it presses on the ground only with a residual weight and consequently with a slight pressure, in order to be able to follow the irregularities of the ground via skates, running wheels or its ground trough itself for longitudinal copying. For keeping to a set value for the ground pressure either by means of suitable sensors, the pressure in the hydraulic cylinders or the supporting force of the hydraulic cylinders on the chassis of the harvesting machine is monitored. In the event of a deviation from this set value the piston rods of the hydraulic cylinders are driven so far in or out until the set value again prevails, which is associated with a raising or lowering of the attachment. For transverse copying the attachment is equipped in its outer side regions with sprung elastic slide hoops, which detect the ground and via a potentiometer connected to them furnish a measure of the distance of the attachment from the ground. If the signals from both sides differ from each other, two further hydraulic cylinders have pressure applied to them, which are applied in a vertical direction between for example the feeder shaft of the combine harvester and the attachment, which tilt the attachment laterally until on both sides of the attachment the same distance is restored again.

[0004] As regards this device for ground copying, it can be criticised on the one hand since because of the constantly flowing hydraulic oil it reacts to a considerable degree much too sluggishly. On the other hand it delivers the control signal for longitudinal copying much too late. Furthermore there is a disadvantage that through ground detection under different weather conditions, through constantly changing leverage ratios and hysteresis phenomena in the lifting system and through the influence of markedly fluctuating dynamic forces, practically no reproducible set values for ground pressure can be realised. The consequence of this is that obstacles cannot be avoided and its operability is put into question even at moderate driving speeds.

[0005] The second category of devices for ground copying, one embodiment of which is described in EP 0 748 153 B1, works alongside the facility proposed in the first category via direct ground contact of the attachment now principally without this. For this, ultrasound sensors are fixed on both sides in the region of its sidewalls, which continuously measure the distance of the attachment from the ground and produce a corresponding output signal. In the driver's cab of this harvester a control device is installed, which receives the output signals from the ultrasound sensors and in the event of a deviation from a prescribed set value for the distance it addresses a control valve in the hydraulic circuit of the hydraulic cylinder for raising and lowering the attachment. Since the hydraulic cylinder is arranged analogously to the solution described in the foregoing and is actuated likewise, this system operates just as sluggishly and imprecisely as regards adherence to the set value for the distance between the attachment and the ground. The ultrasound sensors present an additional disturbing factor, as they cannot distinguish between plants or stubble lying on the ground and the ground itself, so that under these conditions they deliver false distances. Because of their arrangement just above the ground, these errors are made especially noticeable. Furthermore, ultrasound sensors react to wind and humidity with a large scattering of the measured values. In addition they are relatively expensive to purchase, so that all these disadvantages taken together could be the reason that such a device for ground copying has not been accepted in practice.

[0006] Setting out from the negative experiences from the afore-described solution, a further device for ground copying has been published in EP 0 511 768 B1and EP 0 936 475 A1, where the ultrasound sensors employed there are fixed far above the ground and in the side region of the attachments. With this it is achieved that only the measurement error for distance caused by stubble or plants lying on the ground is diminished somewhat as a percentage.

[0007] A further possibility for a device for ground copying by means of ultrasound sensors is described in EP 0 765 594 A1 with an example of a combine harvester cutter. There the ultrasound sensors measure continuously the distance to the sensor skids attached to the exterior of the cutter with the aid of a plate attached to them, in order to exclude the error from ground sensing. However this measure alone is not sufficient for well-functioning ground copying. Furthermore, the angle of incidence and emission to the plate varies constantly, so that distortions to the measurement of distance occur.

[0008] To be assessed analogously is the ground copying in accordance with DE 196 01 420 A1, where a prestressed sliding element of narrow spring steel senses the ground and transmits its movement in consequence of ground irregularities to a signal transmission element. This is formed as a parallelogram of rods, to which a plate is attached, which in contrast to the previously described plate on the sensor skid executes approximately parallel movements. This is irradiated by a wave sensor and reflects its radiation. From this the wave sensor determines a measure for the change in position of the sliding element, which is in a directly proportional ratio to the distance of the attachment from the ground. The measure thus determined with a somewhat greater accuracy, is however used finally also only for driving a control valve in the hydraulic circuit for the hydraulic cylinder for raising and lowering the front attachment, so that all the previously mentioned disadvantages cannot be removed even with this ground copying. An additional deficiency is caused by the narrow sliding elements in the presence of longitudinal grooves in the ground, as they then indicate a false distance.

[0009] Therefore the objective of the invention is to create a device for ground copying for front attachments to harvesting machines, which reacts rapidly to irregularities in the ground, even at higher driving speeds, which adheres with greater precision to the distance of the attachment from the ground, which is prescribed as the set value, and which is manufacturable economically.

[0010] This objective is solved according to the invention by the features of the 1^(st) claim, in which the features are listed in the subclaims, which further develop this solution in an advantageous manner.

[0011] Through the attachment of the feeder device to the harvesting machine by means of powerful hydraulic cylinders so that its height can be altered, it is possible to tilt this, together with the attachment fixed to the front, through a relatively large range, which is used superficially for adjusting the starting position of the attachment for proper use and raising it to a transport position. Because of the size of this hydraulic cylinder and the flow of large quantities of hydraulic oil associated with it this movement takes quite a long time. Therefore for the purpose of longitudinal copying on the ground, the attachment is fixed to the feeder device so that it can tilt on an axle aligned transversely to the direction of travel of the harvesting machine, so that it can move relative to the fixed feeder device about a defined angle of tilt. For monitoring the defined range for the angle of tilt, a sensor is arranged in a fixed position on the feeder device, which is in contact with the attachment. For the enforced movement of the attachment within the defined range, according to the invention between it and the feeder device a relatively smaller, and hence fast reacting hydraulic working cylinder, is envisaged.

[0012] On the attachment there is at least one further sensor, which constantly measures the distance of the attachment from the ground. Both sensors furnish electrical signals, which are passed on to a controller, which can influence the hydraulic system of the hydraulic cylinder beneath feeder device and that of the hydraulic working cylinder between the feeder device and the front attachment.

[0013] A more expedient embodiment of the device for ground copying in accordance with the invention consists in that the distance of the attachment from the ground is determined by feelers sliding along the ground and which are moveable as regards height relative to the attachment, which transmit their height movement proportionally to so-called angular sensors for producing an appropriate output voltage. In the case of the use of a cutter as an attachment, it is suggested to use as a feeler just the stem divider located in the region of the sidewalls plainly front of the cutter bar.

[0014] In a further advantageous embodiment of the invention it has proved its worth, to suspend the attachment on the feeder device so as to be capable additionally of tilting about an axis pointing in the direction of travel of the harvesting machine for the purpose of transverse copying. A further hydraulic cylinder arranged accordingly between the feeder device and the attachment is likewise connected to the controller, which for its operation utilises the signals from the sensors for measuring the distance.

[0015] The method of functioning of the device for ground copying begins thus, in that a preselection of the mode of operation of the attachment is made through an operating element located in the driver's cab of the harvesting machine, in which the pushbutton for “ground copying” is pressed. Thus the controller designed as a software controller for executing the necessary control and computing operations for ground copying is activated. Then a set-value transmitter is adjusted to the desired set distance of the attachment from the ground, which is conveyed to the controller via its input lead. Also the left and right hand sensors in the stem divider, which continually determine the actual distance of the attachment from the ground, deliver their values and the sensor for monitoring the defined range for the angle of tilt likewise delivers its value to the controller via separate input leads.

[0016] As long as the front attachment is in the transport position or is on the way to its starting position for field use, the two actual distances are greater than the set-value for distance and the controller lowers the feeder device together with the attachment in the direction of the ground. Previously or simultaneously via the hydraulic working cylinder it sets the attachment to the mean value of the defined range for the angle of tilt, the attainment of which is signalled by the sensor between the feeder device and the attachment. Incidentally, so that the attachment when longitudinal copying can follow all ordinarily large bumps and dips in the ground within the defined range for the angle of tilt, it has proved expedient to permit for this about a 10-degree range of freedom. The starting position of the attachment for field use is then reached, if the two actual distances or the average value for actual distance calculated by the controller agree with the set-value for distance, and the hydraulic cylinders thereupon stop the lowering movement of the feeder device.

[0017] The longitudinal copying in field use over above averagely large bumps and dips in the ground is executed by the hydraulic working cylinder alone, as long as the angle of tilt lies within its defined range. For this the controller compares the mean actual distance of the attachment from the ground and accordingly controls magnitude of the deviation of the hydraulic working cylinder to a length for immediate readjustment to the set distance. If the attachment encounters above averagely large bumps and depressions in the ground, the angle of tilt attains the upper or lower limit of the defined range. This is reported by the sensor for monitoring the angle of tilt to the controller, which thereupon raises or lowers the feeder device via its hydraulic cylinders so far, until the angle of tilt is again within its defined range. At the same time the hydraulic working cylinder likewise via the control signals from the controller takes care of adherence to the set-value for distance.

[0018] In a further preferred variant embodiment of the invention, the longitudinal copying according to the invention is advantageously combined with simultaneous transverse copying, in which the controller transmits to the hydraulic cylinder a control signal from the difference in the actual distance, which tilts the attachment about an axis which points along the direction of travel of the harvesting machine.

[0019] To sum up, the advantages of the invention are that with it very rapid ground copying has become possible for the front attachment of a harvesting machine, which shows itself particularly at high travelling speeds of the harvesting machine. The sensors which measure the distance of the attachment from the ground in the embodiment of mechanical feelers in conjunction with angular sensors delivering electrical signals furnish the most precise values, so that the attachment can follow the ground contour exactly. Finally, for this device for ground copying only simple components, which are already present on harvesting machines, are necessary so that their costs of manufacture are kept within limits.

[0020] The invention will now be explained in more detail using one example of its embodiment, in which the individual figures show:

[0021]FIG. 1: a side view of the front part of a schematically depicted combine harvester with a feeder shaft and cutter

[0022]FIG. 2: an enlarged section of the lower part of the tilting frame from FIG. 1

[0023]FIG. 3: an electrical/hydraulic circuit diagram of the device for ground copying

[0024] In FIGS. 1 and 2 the device for ground copying is realised with an example of a combine harvester, which possesses a feeder shaft as a feeder device (1) for the material to be threshed, which is fixed on the chassis (3) around its upper shaft axle (2) so that it can be tilted to adjust its height. For this there are between the chassis (3) and the under side of the feeder shaft two hydraulic cylinders (5) fixed one on each side which act on it through articulated joints (4) and (4′). At the front the feeder shaft is equipped with reinforcing frames (6), on the under side of which there is an axle (7) which runs transversely to the direction of travel of the combine harvester. Around this axle (7) is arranged a tilting frame (8) opposite the reinforcing frame (6) so that it can tilt through a defined angle of tilt (9). A hydraulic working cylinder (10), which is joined with articulated joints at one end to the upper side of the feeder shaft and at the other end to the tilting frame (8) forms the connection, which changes the distance between them. A sensor (11) attached to the side of the feeder shaft with its feeler arm (12) touching the tilting frame (8) constantly records the magnitude of the angle of tilt (9).

[0025] Besides the tilting frame (8) is suspended opposite the reinforcing frame (6) so that it can tilt about an axle (13) pointing in the direction of travel of the combine harvester, for which between the feeder shaft and the tilting frame (8) a hydraulic cylinder (14) with articulated joints is arranged vertically on the left side viewed in the direction of travel.

[0026] The tilting frame (8) is designed so that it can rapidly pick up a front attachment (15) for the harvesting machine and deposit again on the ground or a transport lorry, which in this example is a cutter. When ground copying, its cutter bar (16) exhibits a distance (17) from the ground, which is measured constantly on both sides of the attachment (15) with a sensor (18) on each side. The sensors (18) which are designed as angular sensors are coupled for this with the stem dividers (19) of the attachment (15), which are adjustable in height and slide on the ground, are coupled in such a manner that their movement in height is transferable proportionally to the tilting movement of the sensors (18).

[0027] The electrical/hydraulic circuit diagram of FIG. 3 conveys an overview of all the control and operating elements necessary for ground copying and of their interaction in the circuit. For this the harvesting machine is equipped at a suitable place with a hydraulic variable displacement pump (20), which is connected with a hydraulic positioning device (21). Its suction pipe (22) and overflow oil pipe (23) and the return flow pipe (24) of the entire hydraulic system end together in the hydraulic oil reservoir (25). Its pressure pipe (26) is connected on the one hand via a current regulator for lifting (27) and a logic element (28) with the hydraulic cylinders (5) beneath the feeder shaft. On the other hand there is a connection between the hydraulic cylinders (5) and the return flow pipe (24) via the logic element (28) and an electrical shut-off valve (29) as well as a current controller for lowering (30).

[0028] On the other hand, the pressure pipe (26) is connected via a 4/3-way proportional valve (31) and a simple lowering brake valve (32) with the hydraulic working cylinder (10) for longitudinal copying and in addition via another 4/3 -way proportional valve (33) and a double lowering brake valve (34) with the hydraulic cylinder for transverse copying.

[0029] To the electrical part of ground copying belongs an operating unit (35) for preselecting the options for employment of the attachment (15), for which a pushbutton (36) for manual control, a pushbutton (37) for high cutting, a pushbutton (38) for regulation of supporting pressure and finally a pushbutton (39) for ground copying of the attachment (15) are available. The operating unit (35) is connected with a controller (40), which is designed as a software controller for executing control and computing operations. It gets via an input lead (41) from a set value transmitter (42) the default value for a set distance measure (17) for the attachment (15) from the ground, via the input leads (43;43′) the actual distance (17) from the sensors (18) and via input lead (44) from sensor (11) the actual value for the angle of tilt (9). For outputting its control signals it possesses output leads (45;45′) leading to the current regulator for raising (27) and to the current regulator for lowering (30) respectively, for the hydraulic cylinder (5), an output lead to the electrical shut-off valve (29), output leads (47;47′) to the 4/3-way proportional valve (31) for the hydraulic working cylinder (10) and output leads (48;48′) to the 4/3-way proportional valve (33) for the hydraulic cylinder (14).

[0030] Furthermore, the controller (40) is connected with a hand lever (49), from which it receives control signals for manual control of the front attachment (15). 

1. A device for ground copying for attachments to harvesting machines, in particular for self-propelled combine harvesters and forage harvesters, with: a feeder device (1) the height of which can be altered by tilting by means of hydraulic cylinders (5), to the front side of which the attachment (15) is fixed, on the attachment (15) are fixed sensors (18) for measuring the distance (17) of the attachment from the ground, which are connected via a controller (40) to at least the hydraulic system of the hydraulic cylinder (5) for the feeder device (1), characterised in that a) the feeder device (1) possesses an axle (7) arranged horizontally and transversely to the direction of travel of the harvesting machine, to which the attachment (15) is fixed so that it can tilt about a defined angle of tilt (9) relative to the feeder device (1), b) between the feeder device (1) and the attachment (15) a hydraulic working cylinder (10) is arranged for altering the angle of tilt (9) within a defined range, c) a sensor (11) is provided for monitoring the defined range of the angle of tilt (9), which is connected via the controller (40) to the hydraulic system of the hydraulic cylinder (5) of the feeder device (1) and of the hydraulic working cylinder (10) for varying the angle of tilt (9), d) the sensors (18) fixed to the attachment (15) for measuring its distance from the ground (17) are connected via the controller (40) with the hydraulic system of the hydraulic cylinder (5) of the feeder device (1) and the of the hydraulic working cylinder (10) for varying the angle of tilt (9).
 2. A device in accordance with claim 1, characterised in that, the sensors (18) on the attachment (15) are coupled with mechanical feelers sliding on the ground, which are movable as regards height relative to the attachment (15) and which in the case of a cutter are located viewed in the direction of travel of the harvesting machine well in front of its cutter bar (16) and in the case of a collecting device clearly in front of its pick up drum.
 3. A device in accordance with claims 1 and 2, characterised in that, the stem dividers (19), the height of which can be varied, which are located in the region of the side walls of the cutter in front of the cutter bar (16), are connected with the sensors (18) for measuring the distance (17) from the ground.
 4. A device in accordance with claims 1 to 3, characterised in that, the defined range for the angle of tilt (9) between the attachment (15) and the feeder device (1) lies in the order of magnitude of 10 degrees.
 5. A device in accordance with claims 1 to 4, characterised in that, between the attachment (15) and the feeder device (1) a hydraulic cylinder (14) which tilts the attachment (15) about an axle (13) pointing in the direction of travel is arranged, the hydraulic system of which is connected via the controller (40) with the sensors (18) for measuring the distance (17) of the attachment (15) from the ground.
 6. A device in accordance with one or more of the foregoing claims, characterised in that, the controller (40) is designed as a software controller, which is connected with at least the input leads (41;43;43′;44) of a set value transmitter (42) for the set distance (17) for the attachment (15) from the ground, the sensors (18) which continuously measure the actual distance (17) and the sensor (11) for monitoring the defined range of the angle of tilt (9) and that it possesses at least output leads (45;45′;47;47′;48;48′) to the hydraulic cylinders (5) of the feeder device (1), to the hydraulic working cylinder (10) between the feeder device (1) and the attachment (15) and to the hydraulic cylinder (14) for tilting the attachment (15) about an axle (13) pointing in the direction of travel.
 7. A device in accordance with one or more of the foregoing claims, characterised in that the controller (40) is connected with an operating unit (35) for preselecting the options for the use of the attachment (15), which possesses at least one pushbutton (36) for manual control, one pushbutton (37) for high cutting, one pushbutton (38) for regulating the supporting pressure and one pushbutton (39) for ground copying.
 8. A device in accordance with one or more of the foregoing claims, characterised in that, the controller (40) is connected with a hand lever (49) for manual control of the attachment (15).
 9. A device in accordance with one or more of the foregoing claims, characterised in that, the mean actual distance (17) of the attachment (15) from the ground calculated by the controller (40) from the actual distances (17) of the sensors (18) is the control signal for the hydraulic working cylinder (10) for readjustment to the set distance (17), so long as the angle of tilt (9) is within the defined range.
 10. A device in accordance with one or more of the foregoing claims, characterised in that, the signal from the sensor (11) monitoring the defined range of the angle of tilt (9), in the event of attaining or exceeding its upper or lower limits, is the control signal for the hydraulic cylinder (5) of the feeder device (1) for readjusting into the defined range with simultaneous adherence to the set distance (17) for the attachment (15) from the ground.
 11. A device in accordance with one or more of the foregoing claims, characterised in that, for setting the initial position of the attachment (15) for ground copying the signal from the sensor (11) monitoring the defined range for the angle of tilt (9) is the control signal for the hydraulic working cylinder (10) for readjusting the angle of tilt (9) to a mean value, and that the mean actual distance (17) of the attachment (15) from the ground calculated by the controller (40) is the control signal for the hydraulic cylinder (5) for the feeder device (1) for setting it to the set distance (17).
 12. A device in accordance with one or more of the foregoing claims, characterised in that the difference from actual distance (17) of the attachment (15) from the ground is the control signal for the hydraulic cylinder (14) which tilts the attachment (15) about the axle (13) pointing in the direction of travel.
 13. A device in accordance with one or more of the foregoing claims, characterised in that, the sensors (18) for the distance (17) and the sensor (11) for monitoring the defined range for the angle of tilt (9) are formed as angular sensors. 